Abstract:To investigate the fine particle emission instantaneous characteristics of a single light-duty gasoline vehicle on Nanjing urban streets, an on-road system of chassis dynamometer was set up to analyze the influences of vehicle speed, acceleration and driving modes on fine particles size distributions. For the on-road measurements, the number and the mass concentration of particles under acceleration condition are obviously higher than those under other driving modes. At low speed, the number concentration of fine particle in nucleic mode(Dp<50 nm) is higher than that at high speed, while the particle numbers in accumulation mode(50 nm<Dp<565 nm) at high speed is more than that at low speed. The average total number concentration in the chassis dynamometer tests is 1.62 times than that in on-road measurements, while the ratio of average mass concentration to that in on-road measurements is only 0.18. The particle number concentration with diameter lower than 100 nm accounts for a vast majority of the test range. More fine particles are emitted under high speed and hard acceleration condition. The results show that the proposed system is effective to investigate the fine particle emission characteristics from a light-duty gasoline vehicle at real urban road.